104 



CALIFORNIA FISH AND GAME. 



which are still wider than the others. This region extends to the edge 

 of the scale, which is rough and broken. In the area marked A-D the 

 circuli are not altogether homogeneous in character, for at B and also 

 at C, two or three of them are closely apposed or narrower than the 

 others. These are the principal structural features of this particular 

 scale. 



Scales from the other marked grilse possess very similar character- 

 istics. These present the same type of nucleus, which is surrounded by 

 two distinct outer areas, the inner of which is much like that of the scale 

 just described. The nucleus, when followed through the entire series 

 of 23 scales, is seen to possess the same closely crowded or narrow cir- 

 culi, although they vary in number from 8 to 14. The area designated 



Fig. 41. 



The racks at Klamathon, between which the returning grilse were 

 trapped. Photograpli by E. A. McGregor. 



as A-D is in cases wider or narrower, but it preserves more or less 

 definitely the same features. The outer area, D-E, varies greatly in 

 width, in some cases being scarcely represented. The irregular edge 

 and the variable width of this outer area are due to absorption which 

 the sfeale has undergone, it having suifered as have some other tissues 

 of the body during the long and difficult migration from the sea, which 

 was performed without food. In grilse taken at the mouth of the river 

 this portion of the scale is perfect, as is illustrated by figure 44. 



It will be of interest to attempt an interpretation of some of the 

 structural features which are apparent in these scales, even in the face 

 of the possibility that such interpretation may not be wholly supported 

 by additional data which it is hoped the future will provide, In the 



